It is 40 years ago this year since Tobe Hooper’s seminal Texas Chainsaw Massacre first traumatised audiences across the world, and to mark the occasion Second Sight are releasing a special restoration edition of the film on Blu-ray later this month.

What can be said about The Texas Chainsaw Massacre that hasn’t already been said in the four decades since its original release? It’s extremely hard to pay justice to the importance of the film, not just in the horror genre, but as a footnote in cinema. “Masterpiece” is a term that gets slung about far too easily in horror these days, but The Texas Chainsaw Massacre is undoubtedly a masterpiece. Initially banned in several countries, stories abounded of its legendary brutality, urban legends sprang up, telling tales of tramps paid thousands of dollars by the film’s producers to have their limbs amputated live on camera. All nonsense, of course; the film is virtually bloodless. But it is a brutal viewing experience, relentless in its delivery of discomfort.

It is not just the violent scenes which are uncomfortable, it was a famously hot shoot and the heat seems to radiate from the screen as you watch. And the film offers no sanctuary, there is no comic relief, no abatement. There is nowhere for the characters or audience to hide under the constant glare of the merciless Texas sun, no dark corners, no shade to shelter in and certainly no light to escape to, because you’re already in it, obvious and vulnerable. Hooper doesn’t even let us have the luxury of incidental music, an absence which suddenly becomes obvious when the audience are allowed one solitary, doom laden note as Leatherface slams the gliding metal door after dispatching Kirk with a hammer. Despite the lack of gore, Daniel Pearl’s camera never flinches from the grim realities of murder; the agony and the spastic death twitches are all there in their unedifying glory.

With 40 years of reviews, revisits and nostalgia to delve into, there seems little point in writing any further about the content the movie. So let’s turn our attention to Second Sight’s 40th anniversary restoration. The film has received a 4K restoration and a 7.1 audio mix. If that means anything to you, then congratulations. But in all seriousness, the movie does look and sound fantastic. Essentially, the restoration has kept the sun-bleached, washed out ambience that adds so much to the film and which would have been a huge loss. The restoration was supervised by Tobe Hooper, so obviously was never going to jeopardise the essence of the film.

However, it is with the bonus features that Second Sight have really excelled themselves. DVD extras are so often lazy, throw away scraps (what’s the attraction with watching an entire movie with the guy who played “second body on the left” doing a crap voice over?), but the second disc of this 40th anniversary restoration is loaded with gems. There are features which have been available before, coupled with those which are brand new for this release.

Notable inclusions are the “Shocking Truth” film, documenting the making of The Texas Chainsaw Massacre, a new audio commentary with Tobe Hooper, “Grandpa’s Tales”, in which actor John Duggan recalls his experience of playing the murderous clan’s patriarch, “Off the Hook”, an interview with Terri McMinn, who played Pam, interviews with Tobe Hooper, writer Kim Henkel and Gunnar Hansen (Leatherface), a tour of the TCM House with Hansen and “Flesh Wounds – Seven Stories of the Saw”, a documentary focusing on seven facets of the film, most notably the recollections of Ed Neal (The Hitchhiker) and Gunnar Hansen.

There is also a collection of previously unseen outtakes, deleted scenes and bloopers. These serve as testament to the power of The Texas Chainsaw Massacre; it is so incongruous and so strangely reassuring to see the occupants of that green van laughing and joking out of character, it’s as though a spell’s been broken. Similarly, seeing Gunnar Hansen stacking it when chasing Burns (or failing to get his chainsaw to start up at critical moments) elicits a feeling which can only be described as some kind of relief that it’s all actually only make believe.

Some of the bonus features do overlap in content (we get three separate visits to the site of the house, for instance), but this is a minor complaint.

The 40th anniversary restoration will be released in two Blu-ray formats, a limited edition two disc steel book with new art work and a standard two disc Blu-ray with a reversible sleeve. If you’re a die hard Texas Chainsaw Massacre fan, you really need to own a copy. If you’re a horror fan and you don’t own a copy of TCM, you should probably buy one. If, like me, you’re a person who fails to see the point in bonus features, you should also probably get a copy of this restoration, just to help you see the light.